Today some vehicles are supplied with side air bag modules. A side air bag module comprises inflatable cushions or curtains that traverse a side portion of the vehicle when they are deployed in accordance with a predetermined activation event. Generally, the device is located along a side of the vehicle in an un-inflated state and upon activation deploys an inflatable curtain along a side portion of the vehicle. Side impact air bags or inflatable cushions are often mounted in close proximity to the vehicle's roof rail, doorframe or center pillars, or in some instances within the side door. Accordingly, the space or housing for the un-inflated air bag is compact and extends along or traverses the window area or frame, as the air bag cannot be installed in the areas comprising the windows. Moreover, it is also desirable to have the inflatable cushion disposed behind a decorative trim portion of the vehicle's interior. Thus, the presence of the side air bag device is not observable to occupants when it is in its un-deployed state.
Substantial efforts have been directed to developing inflatable cushions or curtains having extended periods of inflation, or in other words inflatable cushions that will retain their inflation gases for a period of time after inflation. Some methods for providing this extended period of inflation are to minimize the inflation gas leakage either by providing a one-piece-woven curtain air bag or by applying a sealant at the seams where the two sides of an inflatable cushion are sealed together. However, both of these methods are costly as they add additional manufacturing steps and methods.
Accordingly, it is desirable to provide an air bag module capable of providing an inflatable cushion or curtain with an extended period of inflation.